1. Field of the Invention
The invention relates to the use of polymer powders that are redispersible in water and based on polymers of ethylenically unsaturated monomers, stabilized with a protective colloid, as a binding agent for jointing sand.
2. Description of the Related Art
The laying of cobblestone paving is effected as a rule on a sand bed, loose sand or a sand slurry usually being swept in for filling the joints between the paving stones. A disadvantage thereby is that the sand is removed from the joint in the course of time, for example in the case of frequent rainfall.
EP-A 401674 discloses acid-curing amino resins as binding agents for joint filling materials. DE-A 3726293 discloses joint grouting materials comprising an emulsifiable epoxy resin and quartz sand. DE-A 4421970 describes a joint material comprising quartz sand, quartz powder and a polymer binding agent, liquid polybutadiene binding agents being used. EP-A 968977 relates to joint materials comprising a pasty component comprising synthetic resin dispersion and mineral fillers and a dry component comprising cement and quartz sand. JP-A 05-085792 discloses the use of a mixture of sand and redispersible powder based on polyvinyl esters, specifically vinyl acetate/VeoVa copolymers, as joint filling material. A disadvantage in the case of the reaction-crosslinking systems is the high price thereof and the complicated processing thereof. Joint filling materials comprising liquid binding agents likewise have disadvantages in the processing since they cannot be introduced into the joint by simply sweeping in. Sand mixtures comprising redispersible polyvinyl esters can be readily processed but result in only insufficient strengthening of the joint filling material.